If your mother ever warned you to slow down because you eat too fast, she now has at least one good reason to support her case: Wolfing down food can expand your waistline and take a toll on your heart, a new study from Japan suggests.

Researchers found that people in Japan who were fast eaters were more likely to become obese than those who ate at a slower pace, according to the findings, which were presented today (Nov. 13) at the American Heart Association’s Scientific Sessions meeting in Anaheim, California. [9 New Ways to Keep Your Heart Healthy]

Fast eaters were also more likely to develop a condition known as metabolic syndrome, — a group of symptoms that increase a person’s risk for heart disease and diabetes — compared with people who ate slowly, the study found. A person is considered to have metabolic syndrome when he or she has three of the following five risk factors: abdominal obesity, high blood sugar, high blood pressure, high triglycerides and low HDL, or “good,” cholesterol.

his is not the first time that researchers have identified health risks associated with eating too quickly: Previous studies have shown that a faster eating speed can contribute to the development of obesity, said lead author Dr. Takayuki Yamaji, a cardiologist at Hiroshima University in Japan. But little was known about the relationship between eating speed and the risk of developing metabolic syndrome, he said.

In the new study, the researchers looked at about 1,100 people in Japan with an average age of 51. All of the participants had a physical exam after enrolling in the study and answered questions about their diet, lifestyle habits and medical history.

At the beginning of the study, none of the men or women had metabolic syndrome, but five years later, 84 people had developed the condition.

Fast-eating risks

To evaluate eating speed, participants were asked to assess how fast they ate compared to other people.

About 6 percent of participants reported they were slow eaters, 32 percent said they were fast eaters, and the rest rated themselves as “medium” eaters, which was considered a normal eating speed in the study, Yamaji told Live Science. Men were more likely to eat quicker than women, he added.

The study showed that after five years, about 12 percent of the people in the fast-eating category developed metabolic syndrome, compared with about 2 percent of the slow eaters and about 6 percent of the normal eaters.

One reason why eating speed may affect heart health and a person’s waistline is that someone who eats too quickly tends not to register feeling full while eating, Yamaji said. As a result, that person is more likely to overeat and consume too many calories, which can cause future obesity, he said.

Although this study only looked at people in Japan, Yamaji said he suspects the findings may also apply to people in other countries.

The results showed that a faster eating speed was linked with more weight gain, higher blood sugar levels and larger waistlines, Yamaji said. This would likely be true of people in other countries, he added.

The good news is that people can learn to slow their eating speed and to savor the taste of each morsel. Some tricks are to take smaller bites of food and to chew each bite very slowly, before eating more, Yamaji said. Other tips are to eat regularly to avoid becoming overly hungry, and to put down your eating utensil between bites.